1. Field of the Invention
The present invention relates to heating systems, more particularly, to radiant heating systems for commercial and residential buildings.
2. The Prior Art
Radiant heating systems are alternatives to the conventional heating systems such as forced hot air, radiators, and baseboards. The typical radiant heating system consists of a boiler for heating water, a pump, a supply pipe, a flexible heating pipe embedded throughout the floor of the room to be heated, a return pipe, and a thermostat for regulating the boiler. Heated water is pumped from the boiler, through the supply pipe, the heating pipe, and the return pipe back to the boiler. These systems have several advantages over other heating systems. They provide uniform heat to the room. In other words, the source of the heat is not localized, like with a forced hot air, radiator, or baseboard system. And because of this, the heating water only has to be heated to a temperature that is a bit above the desired room temperature. For example, if the desired room temperature is 70.degree. F., the water may only have to be heated to about 90.degree. F., depending upon the outside temperature, as opposed to 180.degree. for other heating systems.
There are several methods in the prior art for installing the pipe for a radiant heating system. In the method shown in FIG. 2, the pipe 20 is laid out on the subfloor 22 in a zigzag pattern to cover the entire room. Then concrete or other hardening underlayment 24 is poured over the pipes 20 to a depth of typically about one to two inches. After the underlayment 24 hardens, securing the pipes 20 in place, the flooring 26 is put down. As the heated water heats the underlayment 24, the heat disperses through the underlayment 24 so that the upper surface 28 of the underlayment 24 is uniformly warm, radiating heat uniformly throughout the room.
One shortcoming of this methods is that it is time-consuming to install. The pipes 20 must be laid out by hand, with the correct or desired spacing, and secured in place, a time consuming and relatively exacting process. Then the underlayment 24 must be poured, which takes time to set. Another shortcoming is that the pipes 20 are in direct contact with the subfloor 22, causing some heat to be conducted away from the underlayment 24, essentially wasting some heat energy. Finally, the underlayment 24 adds a substantial amount of weight to the structure.
In the second method, shown in FIG. 3, wood planks 30 are laid down on the subfloor 32, leaving gaps 34 in between. Metal, typically aluminum, brackets 36 with an inverted omega-shaped groove 40 are mounted to the planks 30 with the groove 40 within the gap 34. The pipe 38 is snapped into the groove 40 to secure it in place. The flooring 42 is laid over the planks 30. The omega-shaped groove 40 surrounds the pipe 38 to conduct heat into the bracket to provide greater area coverage and to at least partially uniformly disperse the heat from the pipes 38, similarly to the underlayment 24 of FIG. 2.
The main shortcoming of this method is that it is time-consuming to install. The planks must be placed with the correct gap, a time-consuming process. Then a large number of brackets must be secured to the planks, also a time-consuming process. Another shortcoming is that some heat is directed away from the flooring and into the subfloor. The brackets are mounted to the planks, which conduct some heat from the brackets, and the planks are mounted to the subfloor, again conducting heat from the planks and away from the flooring.
U.S. Pat. Nos. 5,292,065 and 5,579,996, issued to Fiedrich, disclose a method of modularizing the construction of the installation method of FIG. 3, saving much installation time. In these patents, two planks with a gap in between are attached in the underside by a spiked plate. The plank edges that form the gap are dadoed or beveled so that the pipe can be snapped into the gap and retained there. The modules (without the pipe) are nailed to the subfloor with the gaps forming the pattern for the pipe, the pipe is snapped into the gap, and the flooring is laid over the modules. Alternatively, a conductive sheet with a semi-round groove is inserted into the gap and the pipe is inserted into to the groove. The main shortcoming of this method is that the heat is not dispersed very uniformly unless the grooved conductors are used, which, like the omega-shaped brackets, are time-consuming to install. Another shortcoming is the weight of the modules. The modules are made relatively thin, limited to about 1/2 inch, in order to keep the weight down. This also means that the pipe inside diameter is limited to an inefficient 5/16 inch so the pipe will fit. Also, the modules need to be kept relatively short, not longer than about five feet, otherwise they are too heavy, particularly if many of them have to be carried during the course of the day. Yet another shortcoming is that the process of manufacturing the module is time-consuming. The process has a number of steps, including cutting the wood, positioning the wood in proper relation to each other, and spiking the plate to the wood.
Thus there continues to be a need for a modularized approach to the installation of radiant heating systems that is fast, that provides uniform and efficient transfer of heat to the flooring, and that is efficient to manufacture.